Summer is road-trip season, so we're taking a culinary tour of America. But because Portland is a city of immigrants from other states, we don't have to leave town to do it. We're traveling to 50 Portland restaurants to try one distinctive food from each state. Our 50 Plates tour continues with a huckleberry milkshake from Idaho, which joined the union on July 3, 1890.

The State: Idaho, the entry point from the Pacific Northwest into the vast wilds of the Rocky Mountains. In many ways, the state is like a smaller, slightly plainer-looking cousin of Oregon, complete with quaint little lakeside beaches and a junior version of the Blazers (that's the Stampede, Portland's D-League affiliate). But Oregonians owe the Gem State more than they might realize: It was Sacagawea, from the land now called Idaho, who led Lewis and Clark to the coast.

The food: The huckleberry was officially designated as Idaho's state fruit in 2000. Smaller than a blueberry and super-sweet, the berries speckle the mountains of the Idaho panhandle in late summer and early Autumn. Fresh-picked huckleberries are most often baked into pies, but they're also used in jams, sauces, and as a staple flavor of ice cream and milkshakes.

Other foods considered and rejected: Yes, we considered the potato. In all its forms. Also in the running were pan-fried mountain trout, venison, wild mushrooms, and an Idaho Spud candy bar.

Get it from: You can get a hot slice of mountain huckleberry pie way out at Government Camp's Huckleberry Inn, where ski bums load up on carbs before hitting the slopes. But if you're trying to stay in Portland, your huckleberry options are slimmer. The "P.R. Nelson" at Blueplate Lunch Counter isn't exactly your standard huckleberry shake—Cascade Glacier's huckleberry ice cream is blended with their housemade "Purple Haze" hibiscus syrup—but it's so good, it's easy to forgive the impurities. The shake is shockingly sweet, with bits of fruit skin, and there's a mountain of whipped cream on top that makes an effective counterbalance to the saccharine berry and hibiscus blend. The fruit probably didn't come from the Idaho hills, but fresh Oregon huckleberries aren't a bad substitute.

Click on the map to see each state's distinctive food and where to get it in Portland.